False detection of rifampicin resistance using Xpert^® MTB/RIF Ultra assay due to an A451V mutation in Mycobacterium tuberculosis.

ABSTRACT:

Background

In a 12 month period, three Irish-born adult cases with pulmonary TB were initially diagnosed by Xpert^® MTB/RIF Ultra assay, which detected a rifampicin resistance-conferring mutation prompting treatment as potential MDR cases.

Methods

Further laboratory investigations on the cultured isolates included GenoType MTBDRplus assay, phenotypic drug susceptibility tests using the BD BACTEC MGIT culture system and MIC broth microdilution tests. Sequencing of the rpoB gene was performed using Sanger sequencing and WGS.

Results

Phenotypic drug susceptibility tests determined the isolates to be rifampicin susceptible. Molecular investigations identified an A451V (codon 532) mutation in the Mycobacterium tuberculosis rpoB gene that has

SUBMITTER: Fitzgibbon MM 

PROVIDER: S-EPMC8355037 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature